Perhaps you could find this specification in numerous cables at home because it's widely used around the world. It's a technical specification that provides the current capabilities, resistance and diameter of the wire.
Sadly, there are manufacturers that do not comply with the standard and print an incorrect number that doesn't qualify for the gauge group, deceiving users.
AWG goes from thin to thicker and the lowest numbers are the greater diameter, so AWG20 has more conductor than AWG22 for example.
In fact, making fakes could mean important savings in copper and tin, while the insulation could be the same, although being illegal those manufacturers should take care about what they do.
To check if the gauge is correct, any user could use a multimeter with accurate resistance measurement measuring the wire itself. So if the resistance per 100 meters is 33 ohms, if the user has 10 meters of course the resistance of the wire should be 3 ohms. If the resistance goes strange, you might have a true fake in your hands!
This calculator seems enough for references.